早在上世纪五十年代,学者就"A is N times more than B"的意义展开争论。目前一些权威词典对该表达的理解还未取得一致。本研究利用语料库搜索相关表达并根据上下文或背景资料来进行分析,得出的结论为:1)如果N是比1大的倍数,...早在上世纪五十年代,学者就"A is N times more than B"的意义展开争论。目前一些权威词典对该表达的理解还未取得一致。本研究利用语料库搜索相关表达并根据上下文或背景资料来进行分析,得出的结论为:1)如果N是比1大的倍数,被广泛接受的理解应该是"A比B多N-1倍";2)如果N times替换为小于1的分数或百分数,理解为"A比B多+百分数/分数";3)如果N是表示模糊或夸张概念,可以直接理解为"A比B多N倍"。通过该表达在语料库中出现的频数和其他两种常用倍数表达句式的频数进行比较,发现虽然被定性为"歧义"结构,但是该表达在不同文体中仍然被较广泛使用。展开更多
Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show ...Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition tim- ing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its appli- cation, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recir- culation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.展开更多
Time synchronization(TS)is crucial for ensuring the secure and reliable functioning of the distribution power Internet of Things(IoT).Multi-clock source time synchronization(MTS)has significant advantages of high reli...Time synchronization(TS)is crucial for ensuring the secure and reliable functioning of the distribution power Internet of Things(IoT).Multi-clock source time synchronization(MTS)has significant advantages of high reliability and accuracy but still faces challenges such as optimization of the multi-clock source selection and the clock source weight calculation at different timescales,and the coupling of synchronization latency jitter and pulse phase difference.In this paper,the multi-timescale MTS model is conducted,and the reinforcement learning(RL)and analytic hierarchy process(AHP)-based multi-timescale MTS algorithm is designed to improve the weighted summation of synchronization latency jitter standard deviation and average pulse phase difference.Specifically,the multi-clock source selection is optimized based on Softmax in the large timescale,and the clock source weight calculation is optimized based on lower confidence bound-assisted AHP in the small timescale.Simulation shows that the proposed algorithm can effectively reduce time synchronization delay standard deviation and average pulse phase difference.展开更多
Background: Prenatal exposure to illicit substances is responsible for several long-term negative health consequences. It is critical for healthcare professionals to know the extent and scope of prenatal substance exp...Background: Prenatal exposure to illicit substances is responsible for several long-term negative health consequences. It is critical for healthcare professionals to know the extent and scope of prenatal substance exposure in their cases. Several studies exist with mixed results comparing the effectiveness of umbilical cord tissue (UCT) and meconium (MEC) as toxicology specimen types. The specific aim of this study is to compare the use of UCT and MEC regarding the time interval between the birth of the neonate, receipt of the specimen at the laboratory, and the hospital’s receipt of the final toxicology report. Method: The study queried de-identified results of 5358 consecutive UCT and 706 MEC from our laboratory. Results: The mean time from birth to receipt of the specimen at the laboratory for MEC and UCT was 4.5 days ± 2.9 days and 2.8 days ± 1.9 days, respectively. The mean time from birth to final report for MEC was 6.9 days ± 3.8 days, 5.7 days ± 3.3 days, and 8.4 days ± 3.8 days for all MEC specimens, negative MEC, and positive MEC, respectively. The mean time from birth to final report for UCT was 4.3 days ± 2.4 days, 3.5 days ± 2.2 days, and 5.4 days ± 2.2 days for all UCT, negative UCT and positive UCT, respectively. Discussion/Conclusion: Receipt of drug test results of the neonate prior to release from the hospital is critical. This study shows that UCT offers an advantage when results are needed quickly to make informed decisions about the health and well-being of newborns.展开更多
Plants acclimate to drought optimizing the trade-off between biomass production and water loss while ensuring their survival and reproduction. Plants also modify their growth or phenology as complementary strategies i...Plants acclimate to drought optimizing the trade-off between biomass production and water loss while ensuring their survival and reproduction. Plants also modify their growth or phenology as complementary strategies in response to stress. Despite evidence of an interaction between flowering time and plant growth response to environmental stresses, this interaction in response to drought is under debate. To contribute to the analysis of this interaction, leaf growth of 35 genetically modified lines of Arabidopsis thaliana and their common wild-type, Col-0 was analyzed by a quantitative multi-scale phenotyping approach from cellular to whole plant scale both in well-watered and soil moderate water deficit conditions. These genotypes were selected for the various physiological functions potentially altered by their genetic modification and that could interact with plant growth and/or their drought responses. In all genotypes, leaf expansion decreased in response to drought both at the whole rosette and the individual leaf levels. Additionally, epidermal cell area and/or epidermal cell number decreased in response to the drought treatment. In contrast, the number of rosette leaves was reduced in only half of the genotypes and leaf growth duration was only modified in 4 of them. Despite long photoperiod conditions, the duration of the vegetative phase, i.e. the time elapsed between germination and flowering stage, varied from 12 to 27 days among genotypes under well watered conditions. Our analyses revealed that the differences of flowering time observed in well-watered condition impacted the leaf area response to drought. Early-flowering genotypes slightly decreased their final leaf number, but strongly reduced their individual leaf area compared with the late-flowering ones. This result underlines the difficulty to analyze plant response to environmental stresses when genotypes with different flowering dates are compared.展开更多
The exponentially-distributed random timestepping algorithm with boundary test is implemented to evaluate the prices of some variety of single one-sided barrier option contracts within the framework of Black-Scholes m...The exponentially-distributed random timestepping algorithm with boundary test is implemented to evaluate the prices of some variety of single one-sided barrier option contracts within the framework of Black-Scholes model, giving efficient estimation of their hitting times. It is numerically shown that this algorithm, as for the Brownian bridge technique, can improve the rate of weak convergence from order one-half for the standard Monte Carlo to order 1. The exponential timestepping algorithm, however, displays better results, for a given amount of CPU time, than the Brownian bridge technique as the step size becomes larger or the volatility grows up. This is due to the features of the exponential distribution which is more strongly peaked near the origin and has a higher kurtosis compared to the normal distribution, giving more stability of the exponential timestepping algorithm at large time steps and high levels of volatility.展开更多
AIM To evaluate the impact of the timing of capsule endoscopy(CE) in overt-obscure gastrointestinal bleeding(OGIB). METHODS Retrospective, single-center study, including patients submitted to CE in the setting of over...AIM To evaluate the impact of the timing of capsule endoscopy(CE) in overt-obscure gastrointestinal bleeding(OGIB). METHODS Retrospective, single-center study, including patients submitted to CE in the setting of overt-OGIB between January 2005 and August 2017. Patients were divided into 3 groups according to the timing of CE(≤ 48 h; 48 h-14 d; ≥ 14 d). The diagnostic and therapeutic yield(DY and TY), the rebleeding rate and the time to rebleed were calculated and compared between groups. The outcomes of patients in whom CE was performed before(≤ 48 h) and after 48 h(> 48 h), and before(< 14 d) and after 14 d(≥ 14 d), were alsocompared.RESULTS One hundred and fifteen patients underwent CE for overt-OGIB. The DY was 80%, TY-46.1% and rebleeding rate-32.2%. At 1 year 17.8% of the patients had rebled. 33.9% of the patients performed CE in the first 48 h, 30.4% between 48 h-14 d and 35.7% after 14 d. The DY was similar between the 3 groups(P = 0.37). In the ≤ 48 h group, the TY was the highest(66.7% vs 40% vs 31.7%, P = 0.005) and the rebleeding rate was the lowest(15.4% vs 34.3% vs 46.3% P = 0.007). The time to rebleed was longer in the ≤ 48 h group when compared to the > 48 h groups(P = 0.03).CONCLUSION Performing CE within 48 h from overt-OGIB is associated to a higher TY and a lower rebleeding rate and longer time to rebleed.展开更多
读了詹尔震同志的《浅谈“A Is Three Times Larger Than B”句型的汉译》一文(载本刊80年第三期),深有同感。这个问题近年来在我国英语刊物上讨论颇多,但在英美语法书和惯用法词典中却很少谈及。主要原因是它是一种能引起岐义的句型,...读了詹尔震同志的《浅谈“A Is Three Times Larger Than B”句型的汉译》一文(载本刊80年第三期),深有同感。这个问题近年来在我国英语刊物上讨论颇多,但在英美语法书和惯用法词典中却很少谈及。主要原因是它是一种能引起岐义的句型,按一些语法学家的意见,应该列为禁忌,在写作中避免使用。詹文引用了两位美国语言学家对这个问题的论述。展开更多
In the Internet of Things(IoT)system,relay communication is widely used to solve the problem of energy loss in long-distance transmission and improve transmission efficiency.In Body Sensor Network(BSN)systems,biosenso...In the Internet of Things(IoT)system,relay communication is widely used to solve the problem of energy loss in long-distance transmission and improve transmission efficiency.In Body Sensor Network(BSN)systems,biosensors communicate with receiving devices through relay nodes to improve their limited energy efficiency.When the relay node fails,the biosensor can communicate directly with the receiving device by releasing more transmitting power.However,if the remaining battery power of the biosensor is insufficient to enable it to communicate directly with the receiving device,the biosensor will be isolated by the system.Therefore,a new combinatorial analysis method is proposed to analyze the influence of random isolation time(RIT)on system reliability,and the competition relationship between biosensor isolation and propagation failure is considered.This approach inherits the advantages of common combinatorial algorithms and provides a new approach to effectively address the impact of RIT on system reliability in IoT systems,which are affected by competing failures.Finally,the method is applied to the BSN system,and the effect of RIT on the system reliability is analyzed in detail.展开更多
The application of tillering fertilizer plays an important role in promoting rice tillering and improving rice yield. However, under the condition of mechanical transplanting, the optimal application time of tillering...The application of tillering fertilizer plays an important role in promoting rice tillering and improving rice yield. However, under the condition of mechanical transplanting, the optimal application time of tillering fertilizer is still unclear. In this study, the early rice cultivar Zhongjiazao 17 and late rice cultivar H You 518 were used as materials, and the effects of different application times of tillering fertilizer on yield and population development of double-cropping rice transplanted by machine were investigated. The tillering fertilizer was applied 7(D07), 10(D10) and 13(D13) d after the transplanting, respectively. The results showed that compared with those in the D07 treatment groups, the yield of early rice in the D10 and D13 treatment groups were reduced by 9.4% and 3.8%, respectively, and the yield of late rice in the D10 and D13 treatment groups were reduced by 4.5% and 12.6%,respectively. However, there were no significant differences in rice yield among the treatment groups. The application time of tillering fertilizer showed significant effects on grain number per panicle and seed setting rate of early rice. The grain number per panicle in the D10 treatment group was significantly lower than that in the D07 treatment group, and the seed setting rate of the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). For the late rice, the effect of application time of tillering fertilizer on effective tiller number was most obvious, and the effective tiller number in the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). Compared with those in the D07 treatment group, the effective tiller numbers, leaf area indexes and biomasses in the D10 and D13 treatment groups were all trended to be decreased. Therefore,to improve the quality of population and fulfill the high-yielding potential of double-cropping rice transplanted by machine, the tillering fertilizer should be applied as early as possible after rice seedlings turn green.展开更多
The formation and dissociation of methane gas hydrate at an interface between synthetic seawater (SSW) and methane gas have been experimentally investigated in the present work. The amount of gas consumed during hyd...The formation and dissociation of methane gas hydrate at an interface between synthetic seawater (SSW) and methane gas have been experimentally investigated in the present work. The amount of gas consumed during hydrate formation has been calculated using the real gas equation. Induction time for the formation of hydrate is found to depend on the degree of subcooling. All the experiments were conducted in quiescent system with initial cell pressure of 11.14 MPa. Salinity effects on the onset pressure and temperature of hydrate formation are also observed. The dissociation enthalpies of methane hydrate in synthetic seawater were determined by Clausius-Clapeyron equation based on the measured phase equilibrium data. The dissociation data have been analyzed by existing models and compared with the reported data.展开更多
AIM To estimate the efficacy of 2 h post-endoscopic retrograde cholangiopancreatography(ERCP) serum amylase levels and other factors for predicting postERCP pancreatitis.METHODS This was a retrospective,single-center ...AIM To estimate the efficacy of 2 h post-endoscopic retrograde cholangiopancreatography(ERCP) serum amylase levels and other factors for predicting postERCP pancreatitis.METHODS This was a retrospective,single-center cohort study of consecutive patients who underwent ERCP from January 2010 to December 2013.Serum amylase levels were measured 2 h post-procedure,and patient- and procedure-related pancreatitis(PEP) risk factors wereanalyzed using a logistic model.RESULTS A total of 1520 cases(average age 72 ± 12 years,60% male) were initially enrolled in this study,and 1403 cases(725 patients) were ultimately analyzed after the exclusion of 117 cases.Fifty-five of these cases developed PEP.We established a 2 h serum amylase cutoff level of two times the upper limit of normal for predicting PEP.Multivariate analysis revealed that a cannulation time of more than 13 min [odds ratio(OR) 2.28,95%CI:1.132-4.651,P=0.0210] and 2 h amylase levels greater than the cutoff level(OR=24.1,95%CI:11.56-57.13,P<0.0001) were significant predictive factors for PEP.Forty-seven of the 55 patients who developed PEP exhibited 2 h amylase levels greater than the cutoff level(85%),and six of the remaining eight patients who developed PEP(75%) required longer cannulation times.Only 2 of the 1403 patients(0.14%) who developed PEP did not exhibit concerning 2 h amylase levels or require longer cannulation times.CONCLUSION These findings indicate that the combination of 2 h post-ERCP serum amylase levels and cannulation times represents a valuable marker for identifying patients at high risk for PEP.展开更多
BACKGROUND The needs for human epidermal growth factor receptor 2(HER-2) and/or programmed death-ligand 1(PD-L1) evaluations in gastric cancer are dramatically increasing. Although the importance of standardization of...BACKGROUND The needs for human epidermal growth factor receptor 2(HER-2) and/or programmed death-ligand 1(PD-L1) evaluations in gastric cancer are dramatically increasing. Although the importance of standardization of sample fixation has been widely recognized, most of the evidence regarding the fixation duration or type of fixing solution are based on breast cancer.AIM To investigate the real effects of fixation conditions on HER-2 testing or PD-L1 testing for gastric cancer using gastrectomy specimens.METHODS Thirty-two patients who underwent gastrectomy for gastric cancer were enrolled.Their resected specimens were each divided into four pieces and fixed in four strictly controlled different durations(6 h, 24 h, and 48 h, and 1 wk) by 10%formalin(n = 22) or 10% neutral buffered formalin(NBF)(n = 10).Immunohistochemistry(IHC) of HER-2 and PD-1 was performed, and a pathology examination was conducted. In the HER-2-immunoreactive cases, all four specimens were subjected to dual-color in situ hybridization(DISH). Five cases were assessed as HER-2-positive by IHC and DISH. We used the cut-off values of 1%, 10%, and 50% to assess the IHC findings of PD-L1.RESULTS No significant difference was observed in comparisons between the shorter fixation period groups(6 h, 24 h, and 48 h) and the prolonged fixation period(1 wk) group in the HER-2 and PD-L1 analyses. Although no significant difference was observed between 10% formalin and 10% NBF within 1 wk of fixation, the superiority of 10% NBF was confirmed in a long-term(> 3 mo) fixation in both the HER-2 and PD-L1 analyses.CONCLUSION In this small-numbered pilot study, prolonged fixation within 1 wk showed no inferiority in HER-2 or PD-L1 testing. However, a large-numbered prospective study is needed to obtain conclusive results.展开更多
Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface te...Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface tensions were calculated from crystallization induction times using classic homogeneous nucleation theory. Induction time and surface tension decreased at higher temperature.展开更多
The approach of Li and Zhou(2014)is adopted to find the Laplace transform of occupation time over interval(0,a)and joint occupation times over semi-infinite intervals(-∞,a)and(b,∞)for a time-homogeneous diffusion pr...The approach of Li and Zhou(2014)is adopted to find the Laplace transform of occupation time over interval(0,a)and joint occupation times over semi-infinite intervals(-∞,a)and(b,∞)for a time-homogeneous diffusion process up to an independent exponential time e_(q)for 0<a<b.The results are expressed in terms of solutions to the differential equations associated with the diffusion generator.Applying these results,we obtain explicit expressions on the Laplace transform of occupation time and joint occupation time for Brownian motion with drift.展开更多
In broadband coherent anti-Stokes Raman scattering (CARS) spectroscopy with supercontinuum (SC), the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of variou...In broadband coherent anti-Stokes Raman scattering (CARS) spectroscopy with supercontinuum (SC), the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science.展开更多
As one of the basic inventory cost models, the (Q, τ)inventory cost model of dual suppliers with random procurement lead time is mostly formulated by using the concepts of "effective lead time" and "lead time de...As one of the basic inventory cost models, the (Q, τ)inventory cost model of dual suppliers with random procurement lead time is mostly formulated by using the concepts of "effective lead time" and "lead time demand", which may lead to an imprecise inventory cost. Through the real-time statistic of the inventory quantities, this paper considers the precise (Q, τ) inventory cost model of dual supplier procurement by using an infinitesimal dividing method. The traditional modeling method of the inventory cost for dual supplier procurement includes complex procedures. To reduce the complexity effectively, the presented method investigates the statistics properties in real-time of the inventory quantities with the application of the infinitesimal dividing method. It is proved that the optimal holding and shortage costs of dual supplier procurement are less than those of single supplier procurement respectively. With the assumption that both suppliers have the same distribution of lead times, the convexity of the cost function per unit time is proved. So the optimal solution can be easily obtained by applying the classical convex optimization methods. The numerical examples are given to verify the main conclusions.展开更多
文摘早在上世纪五十年代,学者就"A is N times more than B"的意义展开争论。目前一些权威词典对该表达的理解还未取得一致。本研究利用语料库搜索相关表达并根据上下文或背景资料来进行分析,得出的结论为:1)如果N是比1大的倍数,被广泛接受的理解应该是"A比B多N-1倍";2)如果N times替换为小于1的分数或百分数,理解为"A比B多+百分数/分数";3)如果N是表示模糊或夸张概念,可以直接理解为"A比B多N倍"。通过该表达在语料库中出现的频数和其他两种常用倍数表达句式的频数进行比较,发现虽然被定性为"歧义"结构,但是该表达在不同文体中仍然被较广泛使用。
基金This work was supported by the Natural Science Foundation of Anhui Province (No.090412030).
文摘Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition tim- ing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its appli- cation, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recir- culation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.
基金supported by Science and Technology Project of China Southern Power Grid Company Limited under Grant Number 036000KK52200058(GDKJXM20202001).
文摘Time synchronization(TS)is crucial for ensuring the secure and reliable functioning of the distribution power Internet of Things(IoT).Multi-clock source time synchronization(MTS)has significant advantages of high reliability and accuracy but still faces challenges such as optimization of the multi-clock source selection and the clock source weight calculation at different timescales,and the coupling of synchronization latency jitter and pulse phase difference.In this paper,the multi-timescale MTS model is conducted,and the reinforcement learning(RL)and analytic hierarchy process(AHP)-based multi-timescale MTS algorithm is designed to improve the weighted summation of synchronization latency jitter standard deviation and average pulse phase difference.Specifically,the multi-clock source selection is optimized based on Softmax in the large timescale,and the clock source weight calculation is optimized based on lower confidence bound-assisted AHP in the small timescale.Simulation shows that the proposed algorithm can effectively reduce time synchronization delay standard deviation and average pulse phase difference.
文摘Background: Prenatal exposure to illicit substances is responsible for several long-term negative health consequences. It is critical for healthcare professionals to know the extent and scope of prenatal substance exposure in their cases. Several studies exist with mixed results comparing the effectiveness of umbilical cord tissue (UCT) and meconium (MEC) as toxicology specimen types. The specific aim of this study is to compare the use of UCT and MEC regarding the time interval between the birth of the neonate, receipt of the specimen at the laboratory, and the hospital’s receipt of the final toxicology report. Method: The study queried de-identified results of 5358 consecutive UCT and 706 MEC from our laboratory. Results: The mean time from birth to receipt of the specimen at the laboratory for MEC and UCT was 4.5 days ± 2.9 days and 2.8 days ± 1.9 days, respectively. The mean time from birth to final report for MEC was 6.9 days ± 3.8 days, 5.7 days ± 3.3 days, and 8.4 days ± 3.8 days for all MEC specimens, negative MEC, and positive MEC, respectively. The mean time from birth to final report for UCT was 4.3 days ± 2.4 days, 3.5 days ± 2.2 days, and 5.4 days ± 2.2 days for all UCT, negative UCT and positive UCT, respectively. Discussion/Conclusion: Receipt of drug test results of the neonate prior to release from the hospital is critical. This study shows that UCT offers an advantage when results are needed quickly to make informed decisions about the health and well-being of newborns.
文摘Plants acclimate to drought optimizing the trade-off between biomass production and water loss while ensuring their survival and reproduction. Plants also modify their growth or phenology as complementary strategies in response to stress. Despite evidence of an interaction between flowering time and plant growth response to environmental stresses, this interaction in response to drought is under debate. To contribute to the analysis of this interaction, leaf growth of 35 genetically modified lines of Arabidopsis thaliana and their common wild-type, Col-0 was analyzed by a quantitative multi-scale phenotyping approach from cellular to whole plant scale both in well-watered and soil moderate water deficit conditions. These genotypes were selected for the various physiological functions potentially altered by their genetic modification and that could interact with plant growth and/or their drought responses. In all genotypes, leaf expansion decreased in response to drought both at the whole rosette and the individual leaf levels. Additionally, epidermal cell area and/or epidermal cell number decreased in response to the drought treatment. In contrast, the number of rosette leaves was reduced in only half of the genotypes and leaf growth duration was only modified in 4 of them. Despite long photoperiod conditions, the duration of the vegetative phase, i.e. the time elapsed between germination and flowering stage, varied from 12 to 27 days among genotypes under well watered conditions. Our analyses revealed that the differences of flowering time observed in well-watered condition impacted the leaf area response to drought. Early-flowering genotypes slightly decreased their final leaf number, but strongly reduced their individual leaf area compared with the late-flowering ones. This result underlines the difficulty to analyze plant response to environmental stresses when genotypes with different flowering dates are compared.
文摘The exponentially-distributed random timestepping algorithm with boundary test is implemented to evaluate the prices of some variety of single one-sided barrier option contracts within the framework of Black-Scholes model, giving efficient estimation of their hitting times. It is numerically shown that this algorithm, as for the Brownian bridge technique, can improve the rate of weak convergence from order one-half for the standard Monte Carlo to order 1. The exponential timestepping algorithm, however, displays better results, for a given amount of CPU time, than the Brownian bridge technique as the step size becomes larger or the volatility grows up. This is due to the features of the exponential distribution which is more strongly peaked near the origin and has a higher kurtosis compared to the normal distribution, giving more stability of the exponential timestepping algorithm at large time steps and high levels of volatility.
文摘AIM To evaluate the impact of the timing of capsule endoscopy(CE) in overt-obscure gastrointestinal bleeding(OGIB). METHODS Retrospective, single-center study, including patients submitted to CE in the setting of overt-OGIB between January 2005 and August 2017. Patients were divided into 3 groups according to the timing of CE(≤ 48 h; 48 h-14 d; ≥ 14 d). The diagnostic and therapeutic yield(DY and TY), the rebleeding rate and the time to rebleed were calculated and compared between groups. The outcomes of patients in whom CE was performed before(≤ 48 h) and after 48 h(> 48 h), and before(< 14 d) and after 14 d(≥ 14 d), were alsocompared.RESULTS One hundred and fifteen patients underwent CE for overt-OGIB. The DY was 80%, TY-46.1% and rebleeding rate-32.2%. At 1 year 17.8% of the patients had rebled. 33.9% of the patients performed CE in the first 48 h, 30.4% between 48 h-14 d and 35.7% after 14 d. The DY was similar between the 3 groups(P = 0.37). In the ≤ 48 h group, the TY was the highest(66.7% vs 40% vs 31.7%, P = 0.005) and the rebleeding rate was the lowest(15.4% vs 34.3% vs 46.3% P = 0.007). The time to rebleed was longer in the ≤ 48 h group when compared to the > 48 h groups(P = 0.03).CONCLUSION Performing CE within 48 h from overt-OGIB is associated to a higher TY and a lower rebleeding rate and longer time to rebleed.
文摘读了詹尔震同志的《浅谈“A Is Three Times Larger Than B”句型的汉译》一文(载本刊80年第三期),深有同感。这个问题近年来在我国英语刊物上讨论颇多,但在英美语法书和惯用法词典中却很少谈及。主要原因是它是一种能引起岐义的句型,按一些语法学家的意见,应该列为禁忌,在写作中避免使用。詹文引用了两位美国语言学家对这个问题的论述。
基金supported by the National Natural Science Foundation of China(NSFC)(GrantNo.62172058)the Hunan ProvincialNatural Science Foundation of China(Grant Nos.2022JJ10052,2022JJ30624).
文摘In the Internet of Things(IoT)system,relay communication is widely used to solve the problem of energy loss in long-distance transmission and improve transmission efficiency.In Body Sensor Network(BSN)systems,biosensors communicate with receiving devices through relay nodes to improve their limited energy efficiency.When the relay node fails,the biosensor can communicate directly with the receiving device by releasing more transmitting power.However,if the remaining battery power of the biosensor is insufficient to enable it to communicate directly with the receiving device,the biosensor will be isolated by the system.Therefore,a new combinatorial analysis method is proposed to analyze the influence of random isolation time(RIT)on system reliability,and the competition relationship between biosensor isolation and propagation failure is considered.This approach inherits the advantages of common combinatorial algorithms and provides a new approach to effectively address the impact of RIT on system reliability in IoT systems,which are affected by competing failures.Finally,the method is applied to the BSN system,and the effect of RIT on the system reliability is analyzed in detail.
基金Supported by Key Project of the National Twelfth-Five Year Research Program of China(2011BAD16B04)"Gan-Po Talent 555"Project of Jiangxi Province[GCZ2012(1)]+2 种基金National Transformation Fund for Agricultural Science and Technology Achievements(2013GB2C500244)Science and Technology Plan of Action for Universities and Colleges in Jiangxi Province(12003)Special Fund for Agro-Scientific Research in the Public Interest(201303102)~~
文摘The application of tillering fertilizer plays an important role in promoting rice tillering and improving rice yield. However, under the condition of mechanical transplanting, the optimal application time of tillering fertilizer is still unclear. In this study, the early rice cultivar Zhongjiazao 17 and late rice cultivar H You 518 were used as materials, and the effects of different application times of tillering fertilizer on yield and population development of double-cropping rice transplanted by machine were investigated. The tillering fertilizer was applied 7(D07), 10(D10) and 13(D13) d after the transplanting, respectively. The results showed that compared with those in the D07 treatment groups, the yield of early rice in the D10 and D13 treatment groups were reduced by 9.4% and 3.8%, respectively, and the yield of late rice in the D10 and D13 treatment groups were reduced by 4.5% and 12.6%,respectively. However, there were no significant differences in rice yield among the treatment groups. The application time of tillering fertilizer showed significant effects on grain number per panicle and seed setting rate of early rice. The grain number per panicle in the D10 treatment group was significantly lower than that in the D07 treatment group, and the seed setting rate of the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). For the late rice, the effect of application time of tillering fertilizer on effective tiller number was most obvious, and the effective tiller number in the D13 treatment group was significantly lower than that in the D07 treatment group(P〈0.05). Compared with those in the D07 treatment group, the effective tiller numbers, leaf area indexes and biomasses in the D10 and D13 treatment groups were all trended to be decreased. Therefore,to improve the quality of population and fulfill the high-yielding potential of double-cropping rice transplanted by machine, the tillering fertilizer should be applied as early as possible after rice seedlings turn green.
基金supported by the University Grant Commission,New Delhi,India,under Special Assistance Program (SAP) to the Department of Petroleum Engineering,Indian School of Mines,Dhanbad,India.
文摘The formation and dissociation of methane gas hydrate at an interface between synthetic seawater (SSW) and methane gas have been experimentally investigated in the present work. The amount of gas consumed during hydrate formation has been calculated using the real gas equation. Induction time for the formation of hydrate is found to depend on the degree of subcooling. All the experiments were conducted in quiescent system with initial cell pressure of 11.14 MPa. Salinity effects on the onset pressure and temperature of hydrate formation are also observed. The dissociation enthalpies of methane hydrate in synthetic seawater were determined by Clausius-Clapeyron equation based on the measured phase equilibrium data. The dissociation data have been analyzed by existing models and compared with the reported data.
文摘AIM To estimate the efficacy of 2 h post-endoscopic retrograde cholangiopancreatography(ERCP) serum amylase levels and other factors for predicting postERCP pancreatitis.METHODS This was a retrospective,single-center cohort study of consecutive patients who underwent ERCP from January 2010 to December 2013.Serum amylase levels were measured 2 h post-procedure,and patient- and procedure-related pancreatitis(PEP) risk factors wereanalyzed using a logistic model.RESULTS A total of 1520 cases(average age 72 ± 12 years,60% male) were initially enrolled in this study,and 1403 cases(725 patients) were ultimately analyzed after the exclusion of 117 cases.Fifty-five of these cases developed PEP.We established a 2 h serum amylase cutoff level of two times the upper limit of normal for predicting PEP.Multivariate analysis revealed that a cannulation time of more than 13 min [odds ratio(OR) 2.28,95%CI:1.132-4.651,P=0.0210] and 2 h amylase levels greater than the cutoff level(OR=24.1,95%CI:11.56-57.13,P<0.0001) were significant predictive factors for PEP.Forty-seven of the 55 patients who developed PEP exhibited 2 h amylase levels greater than the cutoff level(85%),and six of the remaining eight patients who developed PEP(75%) required longer cannulation times.Only 2 of the 1403 patients(0.14%) who developed PEP did not exhibit concerning 2 h amylase levels or require longer cannulation times.CONCLUSION These findings indicate that the combination of 2 h post-ERCP serum amylase levels and cannulation times represents a valuable marker for identifying patients at high risk for PEP.
文摘BACKGROUND The needs for human epidermal growth factor receptor 2(HER-2) and/or programmed death-ligand 1(PD-L1) evaluations in gastric cancer are dramatically increasing. Although the importance of standardization of sample fixation has been widely recognized, most of the evidence regarding the fixation duration or type of fixing solution are based on breast cancer.AIM To investigate the real effects of fixation conditions on HER-2 testing or PD-L1 testing for gastric cancer using gastrectomy specimens.METHODS Thirty-two patients who underwent gastrectomy for gastric cancer were enrolled.Their resected specimens were each divided into four pieces and fixed in four strictly controlled different durations(6 h, 24 h, and 48 h, and 1 wk) by 10%formalin(n = 22) or 10% neutral buffered formalin(NBF)(n = 10).Immunohistochemistry(IHC) of HER-2 and PD-1 was performed, and a pathology examination was conducted. In the HER-2-immunoreactive cases, all four specimens were subjected to dual-color in situ hybridization(DISH). Five cases were assessed as HER-2-positive by IHC and DISH. We used the cut-off values of 1%, 10%, and 50% to assess the IHC findings of PD-L1.RESULTS No significant difference was observed in comparisons between the shorter fixation period groups(6 h, 24 h, and 48 h) and the prolonged fixation period(1 wk) group in the HER-2 and PD-L1 analyses. Although no significant difference was observed between 10% formalin and 10% NBF within 1 wk of fixation, the superiority of 10% NBF was confirmed in a long-term(> 3 mo) fixation in both the HER-2 and PD-L1 analyses.CONCLUSION In this small-numbered pilot study, prolonged fixation within 1 wk showed no inferiority in HER-2 or PD-L1 testing. However, a large-numbered prospective study is needed to obtain conclusive results.
文摘Caffeine nucleation induction times were measured at 30 °C and 40 °C in water and ethanol solvents employing laser light absorption technique. Supersaturation concentrations and liquid/solid phase surface tensions were calculated from crystallization induction times using classic homogeneous nucleation theory. Induction time and surface tension decreased at higher temperature.
基金Supported by the National Natural Science Foundation of China(12271062,11731012)by the Hunan Provincial National Natural Science Foundation of China(2019JJ50405)。
文摘The approach of Li and Zhou(2014)is adopted to find the Laplace transform of occupation time over interval(0,a)and joint occupation times over semi-infinite intervals(-∞,a)and(b,∞)for a time-homogeneous diffusion process up to an independent exponential time e_(q)for 0<a<b.The results are expressed in terms of solutions to the differential equations associated with the diffusion generator.Applying these results,we obtain explicit expressions on the Laplace transform of occupation time and joint occupation time for Brownian motion with drift.
基金Project supported by the National Natural Science Foundation of China(Grant No.60627003)the Foundation for Creative Team in Institution of Higher Education of Guangdong Province,China(Grant No.06CXTD009)
文摘In broadband coherent anti-Stokes Raman scattering (CARS) spectroscopy with supercontinuum (SC), the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science.
基金supported by the National High Technology Research and Development Program of China(863 Program)(2007AA04Z102)the National Natural Science Foundation of China(6087407160574077).
文摘As one of the basic inventory cost models, the (Q, τ)inventory cost model of dual suppliers with random procurement lead time is mostly formulated by using the concepts of "effective lead time" and "lead time demand", which may lead to an imprecise inventory cost. Through the real-time statistic of the inventory quantities, this paper considers the precise (Q, τ) inventory cost model of dual supplier procurement by using an infinitesimal dividing method. The traditional modeling method of the inventory cost for dual supplier procurement includes complex procedures. To reduce the complexity effectively, the presented method investigates the statistics properties in real-time of the inventory quantities with the application of the infinitesimal dividing method. It is proved that the optimal holding and shortage costs of dual supplier procurement are less than those of single supplier procurement respectively. With the assumption that both suppliers have the same distribution of lead times, the convexity of the cost function per unit time is proved. So the optimal solution can be easily obtained by applying the classical convex optimization methods. The numerical examples are given to verify the main conclusions.